Spark plug



UNITED STATES PATENT OFFICE.

HARRY W. ASCHINGER, OF INDIANAPOLIS, INDIANA.

SPARK PLUG- Application filed January 10, 1920. Serial No. 350,622.

To all whom it may concern Be it known that I, HARRY W. AsoHINoER, a citizen of the United States, and a resident of Indianapolis, county of Marion, and State of Indiana, have invented a certain new and useful Spark Plug; and I do hereby declare that the following is a full, clear, andexact description thereof, reference being had to the accompanying drawings, 1n which likenumerals refer to like parts.

This invention relates to new and useful improvements in spark plugs for internal combustion engines and the like, wherein the radiation of the heat formed in the spark plug is adjustable tothe individual plug, which when properly adjusted eliminates the formation of carbon upon the insulator by keeping the same at a temperature where the carbon will not be deposited, and where the positive central electrode will not overheat and cause pre-ignition, and wherein the electrical efiiciency of the plug will always be maintained substantially at a maximum.

One feature of the invention is that when the improved spark plug is used in an internal combustion engine, the fuel consumption of the latter is reduced, since under heavy duty conditions the fuel supplied is more completely burned by the air supplied to the plug, and under low speeds, the engine can be readily throttled without danger of misfiring, due to any improper mixtures of the fuel.

Another feature of the invention is the provision of an improved and novel central electrodeincorporating the invention and combined in the usual manner with standard spark plug parts, whereby the improved spark plug may be very cheaply and easily manufactured.

The full nature of the invention. will be understood from the accompanying drawings and the following description and claims.

In the drawings, which are made a part of this application, Fig. 1 is an elevational view of the spark plug. Fig. 2 is a central cross sectionthereof taken on the line 2-2 of Fig. 1. Fig. 3 is a side view of a valve regulating device.

In the drawings there isshown the preferred embodiment of the invention and the same consists of a novel and improved hollow central electrode, the same being used with the usual standard casing, nut, porcelain insulator and terminal cap to form an improved spark plug.

"Herein there is shown the usual spark plug casing 10 having a lower sleeve portion 11 exteriorly threaded and adapted to ,be screwed into an engine cylinder, and an upper portion 12 herein shown in the form of a nut. Mounted within the casing 10 is an insulator 13, preferably of porcelain and having the usual petticoat 13, a locking nut 14 .minal rod has an ignition portion 21 extending downwardly from said conical shield and in proximity to the usual negative or ground electrodes 22 carried by the sleeve 11.

From the foregoing description it will be understood that within the insulator petticoat there is formed an annular chamber 23 between the electrode and the insulator and the same is prevented from having direct communication with the usual firing chamber 24 of the sleeve 11 by the conical shield 19 on the central electrode. Carbon or oil which may work up into the chamber 23 and the chamber 25, the latter between the sleeve 11 and insulator 13, will be deposited-on the adjacent surfaces, but since the conical shield is of greater diameter than the petticoat and in spaced relation adjacent thereto, the explosive temperatures in the cylinder will be substantially retained at all times within these two chambers.'

This temperature is suflicient to burn all of the carbon deposited on these adjoin ing surfaces, thus preventing pro-ignition which is customary in ordinary spark plugs when the engine is operating under heavy duty conditions.

The longitudinal passage 18 is provided to supply air to the lower portion and conical surface of the conical enlargement 19 of the central electrode. It will be understood that the temperatures in the annular chambers are so high that without means for cooling the electrode, the same will shortly become itted, and then scale and disintegrate.

itting and scaling likewise increase the resistance of the conductor. increases the amount of spark across the terminals decreases. Air passing downthe tube 18 and through the radially extending discharge ports 20 passes upwardly along the conical surface and cools the under face of the shield to prevent the foregoing.

Upon the upper end of the hollow central electrode there is secured the usual binding nut 26 and the spring washer 27. Instead of the terminal cap, which customarily is secured directly to the central electrode, there is herein shown a valve cap 28 having a central opening 29 therein, the same registering with the longitudinal passage 18 in the central electrode. An inlet port 30 is herein shown in one side of the cap and communicates with the opening 29 to supply air to the conical shield on the central electrode.

Herein there is shown a ball check valve 31 to automatically close said inlet port upon the compression stroke of the engine. The inlet. port 30 herein is shown extending through the cap at an angle with the longitudinal axis of the central electrode. In the upper end of said inlet port 30 there is secured an adjustment bolt 32, the same sealing one end of the passage 30 and limiting the travel of the ball 31 therein. The bolt 32 is provided with a screw head 33, so that the bolt may be adjusted in the passage 30. The cap 28 has a central extending terminal portion 34 upon which the usual terminal cap 35 is secured.

0 further regulate the temperature in the annular chambers, there is provided addi tional means for regulating the inlet port 30. A spring cap 36 is pivoted adjacent the inlet so that the cap may close the same. A suitable indicating dial 37 is etched or stamped upon valve cap and an extension 38 of the spring cap 36 cooperates therewith to indicate the amount of inlet opening provided and air supplied. Herein the dial has the letters and S to indicate winter and summer conditions. a

From the foregoing description it will be understood that standard parts have been included in the improved spark plug with As the resistance the combination of a novel and improved hollow central positive electrode and a valve cap cooperating therewith, both being simple in design and exceedingly easy to construct, thereby reducing the manufacturing cost of the improved spark plug to a minimum. WVhile the invention has been described in great detail, it will be understood that the invention is not to be limited thereby.

The invention claimed is:

1. In a spark plug for an engine cylinder the combination with an insulator having a petticoat of a central electrode mounted therein in spaced relation with said petticoat to form an annular channel therebetween wherein high temperatures may be maintained, said electrode having a longitudinal passage therein, and a shield extend ing beneath said petticoat having one face in spaced relation therewith, to substantially close said channel and separate the same from the cylinder said electrode having radially extending discharge ports communicating with said passage to supply air for cooling the other face of said shield.

2. A spark'plug for an engine cylinder, the combination with an insulator having a petticoat, of a hollow central electrode mounted therein in spaced relation with said petticoat to form an annular channel therebetween wherein high temperatures may be maintained, an inverted conical shield upon the lower portion of the electrode having the base of said shield in spaced relation with the petticoat end to substantially close said channel from the cylinder, and a cap secured upon the other end of said central conductor for supplying air to the same, said electrode having a plurality of discharge ports in the lower portion of said shield for discharging the air supplied upon the lower face of the shield to cool the same.

3. In a spark plug the combination with a central electrodehaving a passage therein, of a valve cap positioned upon the terminal end of said electrode and having an inlet port therein communicating with said passage, a check valve in said inlet port, and a spring cap pivoted upon said valve cap adjacent said inlet port for regulating the size of the latter.

In witness whereof, I have hereunto affixed my signature.

HARRY IV. ASCHINGER. 

